IPODLAS—A software architecture for coupling temporal simulation systems, VR, and GIS Daniel Isenegger a, ⁎ , Bronwyn Price b , Yi Wu c , Andreas Fischlin b , Urs Frei c , Robert Weibel a , Britta Allgöwer a a GIS Division, Department of Geography, University of Zurich, Winterthurerstr. 190, 8057 CH—Zurich, Switzerland b Institute of Terrestrial Ecology (Terrestrial Systems Ecology), ETH Zurich (ITÖ), Switzerland c Remote Sensing Laboratories, Department of Geography, University of Zurich, Switzerland Received 6 October 2005; received in revised form 10 October 2005; accepted 11 October 2005 Available online 15 November 2005 Abstract Environmental processes often vary in space and time and act over several scales. Current software applications dealing with aspects of these processes emphasize properties specific to their domain and tend to neglect other issues. For example, GIS prefers a static view and generally lacks the representation of dynamics, temporal simulation systems emphasize the temporal component but ignore space to a great extent, and virtual reality tends to “forget” the underlying data and models. In order to remedy this situation we present an approach that aims to bring together the three domains; temporal simulation systems, GIS, and virtual reality, and to foster the integration of particular functionalities. This paper concentrates on concepts and requirements for the development of a suitable software architecture using case studies and use cases seen from a GIS-based perspective. © 2005 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved. Keywords: GIS; design; integration; simulation; visualization; interoperability; software 1. Introduction and motivation Alpine landscapes are constantly changing, not only in time but also over space. The understanding of spa- tiotemporal processes and their interrelations is central to the understanding of the complex behavior of real world systems (Pang and Shi, 2002). Relevant processes might span over several temporal and spatial scales. Therefore, tools for modeling, analyzing, and visualiz- ing such processes should also be able to operate on diverse spatial and temporal scales. What kind of tools should be considered to meet these requirements? Geo- graphic Information Systems (GIS) provide powerful functionality for spatial analysis, data integration and storage (Nyerges, 1993) and Virtual Reality (VR) sys- tems offer interactive virtual fly-through facilities with highly photo-realistic content (Duchaineau et al., 1997; Meyer et al., 2001). These spatially oriented systems lack the ability to represent temporal dynamics and their concepts of landscape are static (Peuquet and Niu, 1995). GIS are very large systems tending to be mono- lithic, and therefore costly to combine with other sys- tems (Preston et al., 2003). On the other hand, temporal simulation systems (TSS) support the simulation of static and in particular dynamic dependencies. Due to the hierarchical structure of state-of-the-art simulation ISPRS Journal of Photogrammetry & Remote Sensing 60 (2005) 34 – 47 www.elsevier.com/locate/isprsjprs ⁎ Corresponding author. Tel.: +41 1 635 52 57; fax: +41 1 635 68 48. E-mail address: disen@geo.unizh.ch (D. Isenegger). 0924-2716/$ - see front matter © 2005 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved. doi:10.1016/j.isprsjprs.2005.10.003